1. Technical Field
This invention relates to tamper-proof caps for containers, such as blow molded plastic jugs which are widely used in the dairy industry for the expendible packaging of dairy products, such as milk.
2. Description of the Prior Art
Prior caps of this type may be seen in U.S. Pat. Nos. 3,338,446 of August, 1967 to Faulstich, 3,204,799 of September, 1965 to Hunter, 4,037,748 of July, 1977 to Stubbs, 4,166,552 of September, 1979 to Faulstich, 4,202,455 of May, 1980 to Faulstich, 4,484,687 of November, 1984 to Bullock, 4,496,066 of January, 1985 to Bullock, 4,566,601 of January, 1986 to Kunzig, 4,678,094 of July, 1987 to Bullock, 4,699,287 of October, 1987 to Bullock, and 4,903,849 of February, 1990 to Wallman.
It will be seen that the prior art relating to press on caps generally use a flexible peripheral flange at the top of the cap that allows the top section of the cap to be removed only after the lower circumferential portion of the skirt has been removed. Prior to removing the lower circumferential portion of the skirt, the typical flange will flex upwardly when a user attempts to remove the closure as in attempting to tamper with the contents of the container.
In the present invention, the rigid circular flange with its angled gusset therebelow formed on the thin walled circumferential skirt of the cap immediately above the uppermost internal thickened flange not only permits the efficient press on capabilities when the cap is installed on a neck of a container, but resists attempts to remove the cap without removing the tear portion of the circumferential skirt.
Additionally, it provides a rigid finger hold which enables the upper portion of the cap remaining after the lower circumferential tear skirt has been removed to be readily grasped and lifted upwardly and of equal importance it provides a practical finger hold when the upper portion of the cap is replaced on the neck of the container where it will relocate in sealing relation to the container.